Sorry Jason, but as you probably guessed, that feature came quite a while before the designer. Since you can put any keys anywhere with the designer, it was not possible to incorporate the F keys swap-in/out feature.
However, it is possible to run up to 9 different keyboards simultaneously, using the "/IX:" command-line feature in the shortcuts that you use to start the keyboard. Please refer to "Technical Information > Command-Line Switches" in our Help system. I hope this will help.
Please write back if anything isn't clear,
The Lake Software